Chlorophenyl and nitrophenyl
n-(chloroacetyl) carbamates



United States Patent 3,337,600 CHLOROPHENYL AND NITROPHENYLN-(CHLOROACETYL) CARBAMATES Angelo John Speziale, Creve Coeur,,andLowell R. Smith, St. Louis, Mo., assignors to Monsanto Company, St.Louis, Mo., a corporation of Delaware No Drawing. Original applicationSept. 4, 1962, Ser. No. 221,301, now Patent No. 3,213,135, dated Oct.19, 1965. Divided and this application May 13, 1965, Ser. No. 455,631

4 Claims. (Cl. 260-455) This application is a division of copendingapplication Ser. No. 221,301, filed Sept. 4, 1962, and now U.S.3,213,135.

This invention relates to a novel process whereby new and usefulchloroacetyl isocyanates of the formula wherein n is a whole number from1 to 3 are made.

The chloroacetyl isocyanates of this invention are prepared by heatingunder anhydrous conditions to effect evolution of hydrogen chloride amixture of one mole of a chloroacetamide of the formula wherein n is awhole number from 1 to 3 and at least one mole of oxalyl chloride in thepresence of an inert organic liquid, and thereafter distilling from thereaction mass said chloroacetyl isocyanate.

A wide range of reaction conditions can be employed in preparing thesechloroacetyl isocyanates provided the reaction conditions result in theevolution of hydrogen chloride which is a by-product of the reaction. Ingeneral itis preferable to reflux the reaction mixture and whilerefluxing to remove the hydrogen chloride as it forms.Refluxingtemperatures in the range of from about 35 C. to about 100 C.have been found highly desirable. With respect to pressure eitherpressures above or below atmospheric pressure can be employed, howeverin general it is satisfactory to employ atmospheric pressure.

Although theoretically the amide reactant and oxalyl chloride combine inequimolecular amounts to produce the desired isocyanate it isadvantageous to employ an excess of oxalyl chloride, for example up toabout two moles per mole of amide.

The inert organic liquid employed in the process of this invention willbe a liquid alkane or a liquid chlorine substituted alkane or mixturesthereof, e.g. n-pentane, nhexane, 2-methylpentane, 3-methylpentane,n-heptane, 2- methylhexane, dichloromethane, 1,1-dichloroethane, 1,2-dichloroethane, chloroform, carbon tetrachloride, isobutyl chloride, andmixtures thereof. In general it is preferable that the amount of saidinert organic liquid present throughout the course of the reaction bethat at least suflicient to maintain the chloroacetyl isocyanateproduced in solution.

The chloroacetyl isocyanates prepared in accordance with the process ofthis invention include rat-chloroacetyl isocyanate, a,a-dichloroacetylisocyanate and sau a-trichloroacetyl isocyanate. These materials arereadily hydrolyzed and therefore when stored should be kept free ofmoisture, as for example stored under refrigerative conditions either assuch or dissolved in an anhydrous inert solvent.

These chloroacetyl isocyanates react with a variety of compounds toprovide a large number of useful compounds. For example the reacting ofequimolecular proportions of the-chloroacetyl isocyanate (1) and analiphatic alcohol or aliphatic mercaptan of the formula 3,337,600Patented Aug. 22, 1967 'ice RXH wherein X is sulfur or oxygen andwherein R is a C aliphatic hydrocarbyl radical (e.g. methyl, ethyl,isopropyl, amyl, allyl, butenyl, propynyl, etc.) or a chlorinesubstibuted C aliphatic hydrocarbyl radical (e.g. 2-chloroethyl,2,3-dichloropropyl, 2-chloroallyl, 3- chlorobut-2-enyl, etc.) providesesters of the formula ClnCH3-CNHC-XR ll ll which esters are useful asherbicides, e.g. at an application rate of 25 pounds per acre methylN(o,oc,x-tIiChiOI'O- acetyl)carbamate (M.P. l06 C.) exhibited excellentpreemergent control of such narrow leaf plants as brome grass, ryegrass, foxtail, crab grass and sorghum. Other useful esters soobtainable from the appropriate alcohol or mercaptan include isopropylN-(a-chloroacetyDcarbamate (M.P. 10l102 C.), methylN-(u,a-dichloroacetyl)thiolocarbamate, 2-chloroallyl N-'(a,a,utriChlOI0-acetyl)carbamate, etc. (2) and a substituted phenol or thiophenol suchas the various chlorophenols, chlorothiophenols and nitrophenolsprovides esters of the formula wherein X is sulfur or oxygen and whereinR is a phenyl radical having one or more chloro and/ or nitrosubstituents which esters are useful as herbicides, e.g. at anapplication rate of 25 pounds per acre 4-chlorophenylN-(u,u,a-trichloroacetyl)carbamate (M.P. 157 C.) exhibited excellentcontact herbicidal control of narrow leaf and broad leaf plants (3) anda primary or secondary amine of the formula ANH-B wherein A is hydrogenor a C aliphatic radical (e.g. methyl, ethyl, isopropyl, amyl, allyl,propynyl, 2-chloroethyl, 2-chloroallyl, etc.) or a phenyl radical or analkyl substituted phenyl radical or chlorine substituted phenyl radicaland wherein B is a C aliphatic radical (e.g. methyl, ethyl, isopropyl,amyl, allyl, propynyl, 2-chloroethyl, 2-chloroallyl, etc.) or a phenylradical or an alkyl substituted phenyl radical or a chlorine substitutedphenyl radical provides substituted ureas of the formula Cl,,CH -nCNHCNII II 0 o B which esters are useful as herbicides, eg at an applicationrate of 25 pounds per acre excellent control of narrow leaf plants isobtained employing N-(a-chloroacetyD- N-(3,4-dichlorophenyl) urea (M.P.C.), N(a,u,octrichloroacetyl) N (3,4-dichlorophenyl) urea (M.P. C.),N-(u-chloroacetyl)-N-methyl urea (M.P. 19'8- 200 C.), andN-(a-chloroacetyl)-N'-isopropyl-N'-pro pynyl urea (M.P. 76-78 C.). Otheruseful substituted ureas so obtainable from the appropriate amineinclude N-(a,a,a-trichloroacetyl)-N',N'-diallyl urea, N-(Ot-ChiOl'O-acetyl)-N'-allyl urea (M.P. 113-115 C.), N-(ot,ozdi0hl0-roacetyl)-N'-isopropyl N phenyl urea, N-(a-chloroacetyl)-N',N'-dimethylurea (M.P. 82-85 C.), etc.

As illustrative of the method of manufacture of the chloroacetylisocyanates of this invention and the preparation of useful derivativesthereof is the following:

Example I To a suitable reaction vessel equipped with a thermometer,agitator and reflux condenser is charged at room temperature 12.8 partsby weight of cc,oc-diCh1OI03.C6i amide, 13.0 parts by weight of oxalylchloride and 88.2 parts by weight of 1,2-dichloroethane. The so-chargedmass is then heated to reflux while agitating then refluxed (about 83C.) for four hours. Thereafter the resulting mass is subjected to vacuumdistillation and the cut (10.45

parts by weight) taken at 135 C. at 35 mm. of mercury isa,a-dichloroacetyl isocyanate, n;; is 1.4600.

Example I-A To a suitable reaction vessel is charged 3.1 parts by weightof a,a-dichloroacetyl isocyanate dissolved in 25 parts by weight ofdichloromethane. While maintaining the temperature at about C. and withagitation there is added 3.2 parts by weight of 3,4-dichloroanilinedissolved in 25 parts by weight of dichloromethane. The solution is thenconcentrated by boiling off the excess dichloromethane. To the soconcentrated solution is added suflicient hexane to precipitate thedissolved solids. The precipitate is filtered off and dried. The driedproduct (5.8 parts by weight) isN-(a,a-dichloroacetyl)-N'-(3,4-dichlorophenyl) urea which afterrecrystallization is found to melt at 157l59 C.

Analysis.Theory, 8.86% N, 44.88% Cl; found, 8.90% N, 45.25% Cl.

Example I-B Employing the procedure of Example I-A but replacing3,4-dichloroaniline with an equimolecular amount of dimethylamine thereis obtained N-(a,a-dichloroacetyl)- N,N'-dimethylurea.

Example II To a suitable reaction vessel equipped with a thermometer,agitator and reflux condenser is charged at room temperature 16.2 partsby weight of ot,ot,oc-t1'iChl0lO- acetamide, 101 parts by weight of1,2-dichloroethane, and 12.7 parts by weight of oxalyl chloride. Withagitation the so-charged mass is heated to reflux and refluxed (about 80C.) for twenty-four hours. Thereafter the resulting mass is subjected tovacuum distillation and the cut (11.3 parts by weight) taken at 80-85 C.at 20 mm. of mercury is a,a,a-trichloroacetyl isocyanate, n is 1.4755.

Example II-A To a suitable reaction vessel is charged 3.8 parts byweight of a,ot,a-trichloroacety1 isocyanate dissolved in 25 parts byweight of dichloromethane. While maintaining the temperature at about 0C. and with agitation is added 3.2 parts by weight of3,4-dichloroaniline dissolved in 25 parts by weight of dichloromethane.The solution is then concentrated by boiling off the excessdichloromethane. To the so concentrated solution is added suflicienthexane to precipitate the dissolved solids. The precipitate is filteredoff and dried. The dried product (5.6 parts by weight) isN-(a,a,a-trichloroacetyl) N (3,4-dichlorophenyl) urea which afterrecrystallization is found to melt at 175 C.

, Analysis.--Theory, 8.00% N, 50.59% Cl; found, 8.11% N, 50.68% Cl.

Example II-B To a suitable reaction vessel is charged 50 parts by weightof anhydrous methanol. While maintaining the temperature at about 0 C.and with agitation is added dropwise 3.8 parts by weight of colda,a,a-trichloroacetyl isocyanate. The mass is evaporated to dryness invacuo and the residue recrystallized from a dichloromethanehexanemixture and dried. The dried product (44 parts by weight) is methylN-(u,oc,a-trichloroacetyl)carbamate which material melts at 105106 C.

Example 111 4 Example IIIA To a suitable reaction vessel is charged 2.4parts by weight of a-chloroacetyl isocyanate dissolved in 25 parts byweight of dichloromethane. While maintaining the temperature at about 0C. and with agitation there is added 3.2 parts by weight of3,4-dichloroaniline dissolved in 25 parts by weight of dichloromethane.The solution is then concentrated by boiling off the excessdichloromethane. To the so concentrated solution is added sufficienthexane to precipitate the dissolved solids. The precipitate is filteredoff and dried. The dried product (4.5 parts by weight) isN-(u-chloroacetyl)-N'-(3,4-dichlorophenyl) urea which afterrecrystallization is found to melt at 160 C.

Analysis.Theory, 9.95% N, 37.78% Cl; found, 9.947 N, 37.72% Cl.

Example III-B To a suitable reaction vessel is charged 2.4 parts byweight of a-chloroacetyl isocyanate dissolved in 25 parts by weight ofcold dichloromethane. While agitating 2.6 parts by weight of4-chlorophenol is added. The solution is concentrated by boiling oil theexcess dichloromethane. To the so concentrated solution is addedsuflicient hexane to precipitate the dissolved solids. The precipitateis filtered off and dried to give 3.6 parts by weight of 4-chlorophenylN-(a-chloroacetyDcarbamate which after recrystallization is found tohave a melting point of 147-149 C.

Example III-C Employing the procedure of Example III-B but replacinga-chloroacetyl isocyanate with an equimolecular amount ofa,a,a-trichloroacetyl isocyanate there is obtained 4-chlorophenyl N-(a,a,a-trichloroacety1)carbamate, M.P. 155-157 C.

Example Ill-D Employing the procedure of Example III-B but replacing4-chlorophenol with an equimolecular amount of 4- chlorothiophenol thereis obtained as a white solid 4- chlorophenylN-(a-chloroacetyl)thiolocarbarnate.

Example III-E Employing the procedure of Example IIIA but replacing3,4-dichloroaniline with an equimolecular amount of methyl mercaptanthere is obtained methyl N-(a-chloroacetyl)thiolocarbamate, M.P. 134-135C.

The terminus of the reaction is readily determined by observing thecessation of evolution of hydrogen chloride. In the reaction stepbetween the amide and the oxalyl chloride it is desirable that the inertorganic liquid employed have a boiling point below that of the desiredisocyanate product. In instances wherein a precipitate forms either inthe reaction step or during the distillation operation or any timetherebetween it is usually desirable to add sufficient inert organicliquid of any of the aforedescribed types to dissolve the precipitatedsolids. In recovering the isocyanate product it is preferable to conductthe distillation operation under reduced pressure, e.g. at less than 50mm. of mercury, and which pressure permits a distillation temperature ofnot more than C.

While this invention has been described with respect to certainembodiments it is to be understood that it is not so limited and thatvariations and modifications thereof obvious to those skilled in the artcan be made without departing from the spirit or scope of thisinvention.

What is claimed is:

1. An aryl N-(chloroacetyl)carbamate of the formula wherein n is a wholenumber from 1 to 3, wherein X is selected from the group consisting ofsulfur and oxygen, and wherein R is selected from the group consistingof chlorophenyl and nitrophcnyl.

2. 4-chlorophenyl N-(a-chloroacetyl)carbamate.

3. 4-chlorophenyl N-(a,a,a-trichlor0acetyl)carbamate.

4. S-(4-chl0rophenyl) N (a-chloroacetyl)thiolocarbamate.

References Cited UNITED STATES PATENTS 2,306,599 12/1942 Engel et al2'60482 X 2,401,080 5/ 1946 Kilgore et a1. 167-22 2,677,698 5/ 1954Deutschman et a1. 260--479 6 FOREIGN PATENTS 1,081,460 5/1960 Germany.

194,377 2/ 1938 Switzerland.

5 OTHER REFERENCES Kolbezen et al.: Journal of Argicultural and FoodChemistry, vol. 2, pages 864-870.

LORRAINE A. WEINBERGER, Primary Examiner. 10 CHARLES B. PARKER,Examiner.

D. R. MAHANAND, I. R. PELLMAN, K. ROSE,

Assistant Examiners.

1. AN ARYL N-(CHLOROACETYL)CARBAMATE OF THE FORMULA